1. Field of the Invention
The present invention relates to a fan motor driving technology.
2. Description of the Related Art
A computing speed of large scale integrated circuit (LSI) such as central processing unit (CPU) and digital signal processor (DSP) is increased incessantly due to high speed of a personal computer or a workstation over recent years. However, heat generation of the LSI also becomes high as both the computing speed and clock frequency become high. The heat generation from the LSI may induce thermal runaway itself or affect peripheral circuits. Therefore, a suitable thermal cooling of a heat generation body as the representative LSI becomes a very important technology.
A technical example used to cool the LSI may be an air cooling method using a cooling fan. In the above method, for example, the cooling fan is disposed opposite to a surface of the LSI, thereby blowing a cold air toward the surface of the LSI.    Patent Document 1: Japanese Patent Publication No. 7-31190    Patent Document 2: Japanese Patent Publication No. 2001-284868